"But hydrogen is not free, in either dollars or environmental
damage. The hydrogen fuel cell costs nearly 100 times as much per unit
of power produced as an internal-combustion engine. To be price
competitive, 'you've got to be at a nickel a watt, and we're at $4 a
watt,' says Tim R. Dawsey, a research associate at Eastman Chemical
Company, which makes polymers for fuel cells." Matthew L. Wald,
"Questions about a Hydrogen Economy," Scientific American, May 2004, p.
68
**
"Researchers are also trying to use microbes to transform biomass,
including parts of crops that now have no economic value, into hydrogen.
In February researchers at the University of Minnesota and the
University of Parras in Greece announced a chemical rector that
generates hydrogen from ethanol mixed with water. Though appealing, all
these technologies are either unaffordable or unavailable on a
commercial scale and are likely to remain so for many years to come,
according to experts." Matthew L. Wald, "Questions about a Hydrogen
Economy," Scientific American, May 2004, p. 69
**
"or hydrogen could come from the methane in natural gas,
methanol or other hydrocarbon fuel. Natural gas can be reacted with
steam to make hydrogen and carbon dioxide. Filling fuel cells, however,
would preclude the use of natural gas for its best industrial purpose
today: burning in high-efficiency combined-cycle turbines to generate
electricity. That, in turn, might again lead to more coal use.
Combined-cycle plants can turn 60 percent of the heat of burning natural
gas into electricity; a coal plant converts only about 33 percent. Also
when burned, natural gas produces just over half as much carbon dioxide
per unit of heat as coal does, 117 pounds per million Btu versus 212. As
a result, a kilowatt-hour of electricity made form a new natural gas
plant has slightly over one fourth as much carbon dioxide as a
kilowatt-hour from coal." Matthew L. Wald, "Questions about a Hydrogen
Economy," Scientific American, May 2004, p. 69
Received on Sun Apr 18 22:06:28 2004